Treatment of sulphite waste liquor



Jan. 14, 1941. HAHN I TREATMENT OF SULPHITE, WASTE LIQUOR F led Sept; 9, 193a Patented Jan. 14, 1941 UNlTED STATES 2,228,628 I TREATMENT or sULPHI'rE WASTELIQUOR Ludwig Hahn, Cesky Krnmlov, Czechoslovakia,

assignor of one-halfto the firm: Biihmisch- -'Krumauer Maschinenpapier-Fabriken Ignaz Spiro et Siihne,

Aktiengescllschaft, Cesky' Krumlov, Czechoslovakia Application September 9, 1938, Serial naazaoco I In Czechoslovakia April 28, 1937 4 Claims.-

My invention relates to the treatment of sulphite waste liquor for the purpose of utilizing valuable constituents contained in such liquor. It has particular reference to the decomposition, by

5 biological action, of certain organic constituents.

It is an object of my invention to provide a novel and advantageous method of fermenting such organic compounds and quite especially the sugar contained'in sulphite waste liquor for the production of ethyl alcohol and other valuable products without adding nutrient salts.

Other objects of my invention will appear as the specification proceeds.-

It is known that the waste liquor resulting in the boilingof sulphite, pulp contains -39 kilograms sugar per cubic meter, approximately 70% of which can be converted into ethyl alcohol by fermentation. As a. rule .the sulphite waste liquid is freed from gases, neutralized with lime and fermented during 48-72 hours at about C. in large fermenting tanks with an addition of yeast and sulphate and phosphate of ammonia as nutrient salts, the ethyl alcohol formed being distilled ofi, while the residual liquid is withdrawn into a draining ditch.

According to the present invention I am enabled tonot only ferment the sugars contained in sul-v phite waste liquor,'but also to decompose part of the other organic constituents under formation 30 of carbon dioxide and water, without adding any nutrient salts or micro-organisms. ethyl alcohol in this process is nevertheless as high as in the prior art processes. 1

. I have discovered that vegetable matter such :15 as straw, grass, wood wool or wood pulp and the like under-certain conditions cause the formation,

in sulphite waste liquor,- of a fungous culture which decomposes the carbohydrates of the sulphite waste liquor as well as part of its other organic 4 constituents. Quite especially the straw of cereals contains the ferment required for this biological decomposition, which meets the most favorable conditions of life in the sulphite waste liquor without requiring any'addition of nutrient salts.

In the drawing affixed to this specification and forming part thereof an apparatus for carrying out the new process is-illustrated diagrammatically by way of example. f

In practicing my invention 1. mayfor. instance proceed as follows: the sulphite waste liquor is freed-altogether from gases and more particularly SO: and is thereupon neutralized with llme, quicklime, the sludge resulting in causticization or some otheralkaline material. to a pH value of 4 to s. This is best performed in the usual manner ment of gas, occurs.

The yield of the wires 3 in the frame I. Ifstraw, the wires may be spaced about 30' cms. A sieve 5 by contacting in a tank the,hot sulphite waste liquor or cellulose wash with, thecorresponding quantity of the alkaline substance and thereupon blowing air throng the liquid. After the reaction has come to an'end, the neutralizing agent in ex- 5 cess'is allowed to settle down and the clear solu-' tion iswithdrawn into the fermentation tank,

which is charged with the vegetable matter conj 7 taining the ferment. k In order to save the time which is' otherwise re- 10 quired for the fermentation' of the whole of the 'waste liquor, I prefer to breed a fermentati've culture in the laboratory. For-this purpose I pour sulphite waste liquor, which has been freed from gases .and neutralized in the manner mentioned above, over the carrier substance for the fungous culture, preferably over straw, and allow the mixture to stand at 3040' 0. until a vivid develop- About 20 grams straw are employed per liter of, the waste liquor. The cul- 20 ture is preferably bred a thermostat vessel. As soon as the culture has well developed, large quantities of the carrier for the fungous culture arranged in the fermentation tank can be infected therewith. When after some days the culture in 25 the fermentation tank has reached its highest efllcacy, it is able to acclimatize to awide range of temperatures, viz. within the limits of 0 and C. The culture is further highly resistive to chemical'influences and retains its activity at so hydrogen ion concentrations within the range of pH=4 and pH=9. A hydrogen ion concentration between pH=5 and 7.5 has been found to be most favorable. q

Fermentation may for instance be carried out 5 in the apparatus illustrated in the drawing, where I isafermentation tank made of wood, concrete or some other suitable material. Artificial pools may also serve for this purpose. At the bottom of the fermentation tank is spread out the carrier 40 2 of the fungous culture, preferably straw,'at the rate of 2 to 20 kilogramsper 'cubic meter of the tank content. The carrier is presse mployed,

cylinder 5 formed with meshes of about 1' cm.",- is arranged vertically in the middle of the fermentation tank. Into this v.cv lntler extends the suction pipeG of the pumpg'l', which servesto withdraw the liquid from the fermentation tank with- 50 out thecarrier substance'ifbein'g canied along.

When starting operationinlthis planti infect straw or similar vegetable matter arranged in the tank with the cultureQbred-in the laboratory as described above and thereupon means! with in;v

neutralized m liquor freed :from gases.

N nutrient salts are added. A vigorous fermentation sets in and, on being completed after the lapse of 48 to 72 hours, brings about a decomposition of up to 25% of the organic "matter contained in the waste liquor. may vary within the wide limits of 0-70 0., so that the fermentation need not be carried out with low-cooled waste liquor, but may also occur in the open even in the cold season without requiring heating.

After the fermentation has come toan end, the

. fermented waste liquor or cellulose wash is withdrawn by the pump 1 into a draining ditch or may be treated further for the recovery of spirit ac cording to any known method. A fresh portion of neutral sulphite waste liquor or cellulose wash free from gases is then pumped over the fungous culture left on the straw or other carrier substance in the fermentation tank. This fresh batch starts fermenting within a short time. mostly within an hour.- No more fungous cultures need be added nor is any additionof nu-. trient salts made, which distinguishes the new method advantageously from the known methods of operation. Since the new. method does not involve any costs of operation, it allows the biological purification of sulphite waste liquor even in such cases where no products of fermentation may be recovered. Moreover, the waste liquor fermented according to the new. method is still more relieve the draining ditch by the sulphite waste liquors led into same, fermentation is preferably carried out in pools. It is known that the removal of the carbohydrates in the waste liquor is of great importancewithresfl-rd to the handling of waste liquors since the carbohydratw cause a rapid growth of algae; and fungi, particularly of sphae- The temperature of fermentation spasms rotilus natans and leptomitus lacteus. These fimgi develop mainly fungi, the formation of sludge, fermentation and finally putrefaction, whereby the water is spoilt for practical use as well as for fishing.

The present invention allows of freeing the waste liquors at low cost from the carbohydrates. Since.

this treatment does not require any addition of valuable nutrient salts, the process can be carried out even in cases where the ethyl alcohol formed cannot be recovered. In respect to the purification of waste liquors it is of importance that the organic matter is decomposed to a farther extent than in the hitherto known processes for the fermentation of sulphite waste liquor.

Various changes may be made in the details disclosed in the foregoing specification without departing from the invention. or sacrificing the advantages thereof.

I claim:

1. The method of treating sulphite waste liquor for the decomposition of itsorganic constituents by biological action, which comprises causing fermentation of neutralized sulphite waste liquor, freed from gases, in the absence of added nutrient salts and in the presence of vegetable matter carrying fermentative cultures developed on said vegetable matter in the presence of sulphite waste liquor. 4 2. In the process of claim 1, the step of allowing fermentation to proceed 'at a temperature ranging between 0 and 70 0.

3. In the process of claim 1, the step of allowing fermentation to proceed at a temperature ranging between 0 and 70 0., withdrawing the fermented liquor and continuously supplying to the vegetable matter'carl'ying the bred culture fresh portions 'of sulphite waste liquorfor fermentation.

4. The method of claim 1, in which the ethyl alcohol formed by the fermentation is recovered from the liquor-treated.

? LUDWIG HAHN.

v I at the expenseof the sugars which flow into the rivers with the waste liquor and cause much trouble, including the floating of 

